What is a high efficiency Filter, and do I need a high efficiency filter if I have a high efficiency furnace?

What is a high efficiency Filter, and do I need a high efficiency filter if I have a high efficiency furnace?

Filter efficiency refers to the percentage of airborne particles that the filter removes. This is different from the fuel efficiency of your furnace (commonly measured as the AFUE). You can choose either a high-efficiency or a low-efficiency filter for your highly fuel efficient furnace. (Note, however, that failing to change / clean your filter regularly can reduce your furnace’s fuel efficiency.)